1. Field of the Invention
This invention relates to a starting system for an outboard motor.
2. Description of the Related Art
A starting system for an outboard motor internal combustion engine comprises a battery, a starter (starter motor) and ignition (ignition/starter) switch. Among of them, a typical ignition switch has “OFF-ON-START” positions. When the operator inserts an ignition key into the keyhole of the ignition switch and turns it to the “START” position beyond the “ON” position, the battery voltage is supplied to the starter motor (and to the fuel pump and the ignition system, etc.) and other various electric loads including an electronic control unit (ECU), instruments, lamps, etc. to start the engine. After the engine has started, when the operator turns or returns the key to the “ON” position, the battery voltage to the starter motor is discontinued, but it is still supplied to the other electric lords, and the engine continues to run. When the operator turns or returns the key to the “OFF” position, the battery voltage supply to the other electric loads is discontinued and the engine is stopped, as taught, for example, by a manual for Honda outboard motor BF115A/BF130A, 2-20, page 17-29, edited by a department of maintenance materials and published on May, 1998 by Honda Giken Kogyo Kabushiki Kaisha.
Further, in on-road vehicles, their ignition switches are extended to have an additional “ACCESSORY” position. In particular, in a vehicle that stops engine during vehicle stop or a hybrid vehicle (constituted as a hybrid of an internal combustion engine and an electric motor(s)) has a relay, in the circuit between the battery and the ignition/starter switch, operable independently of the operator's key manipulation in such a way that the engine can be stopped and re-started at the “ON” position, as taught in Japanese Laid-Open Patent Application No. 2001-173545.
Aside from the above, in recent outboard motors, mechanisms for steering, shift-changing and throttle are electronically controlled using actuators such as electric motors. It will be convenient for the operator if he or she can operate these mechanisms, especially, the mechanisms for steering and shift-changing even when the engine is stopped, since the boat itself keeps moving after the engine was stopped.
In order to allow the operator to operate the mechanisms when the engine is stopped, i.e., when the key is at the “OFF” position, it will be possible to supply the battery voltage to the electric actuators for the mechanisms all the time at this position. However, if doing so, since idling current leaks to the actuators even if the mechanisms are out of operation, it becomes necessary to add a switch in the circuit in such a way that the operator breaks the connection between the actuators and the battery when the mechanisms are out of operation, or to pull out a cable (extending from the battery terminal to the actuators). This is tedious for the operator and if he or she misses, the battery will be discharged and is finally dead.
Other alternative will be to supply the battery voltage to the actuators when the key is at the “ON” position. Since this can easily stop the battery voltage supply to the actuators to avoid idling current flow by turning the key to the “OFF” position, it can prevent the battery from becoming dead. However, as mentioned above, since the battery voltage is still supplied to various electric loads such as instruments and lamps at the “ON” position, the battery is likely to be dead if the key is kept at the “ON” position for a long period of time when the engine is stopped.
Moreover, the outboard motor engine is equipped with an emergency switch that disconnects the battery from the ignition system in case of emergency, without needing the key to be turned to the “OFF” position. If the engine is stopped by this emergency switch, since the ignition switch remains at the “ON” position, the battery is also likely to be dead if this “ON” position is kept for a long period of time.